Various techniques have been devised for combatting the serious problem of motor vehicular theft. Such techniques generally are in one of a number of categories. First, devices have been provided which basically are nothing more than supplemental switches in the starting circuit which are hidden on the vehicle from view of the would-be thief and which selectively activate and deactivate the starting circuit.
Second, many forms of motion sensors have further been provided for sensing motion of the parked vehicle caused by tampering and the movement imparted to the vehicle by the thief in an attempt to gain entry and start the vehicle. Other types of apparatus sought to detect unauthorized entry into the vehicle and were often variously coupled not only with apparatus for disarming the starting circuit, but with a wide variety of attention getting or warning devices in the form of sirens, flashing lights or the like which sought to ward off the thief and warn the owner or others nearby of the attempted theft.
Each of these prior techniques suffered from numerous deficiencies, many of which were common to all such devices. One of the most serious drawbacks was that such systems were active rather than passive in the sense that they required the owner to repetitively arm and disarm these devices manually. Not only would the owner from time to time forget to arm or disarm the theft prevention system, but this precluded other authorized individuals from using and protecting the vehicle unless they knew precisely the operating procedure of the protection system. Many of these systems are notoriously unreliable, giving rise, for example, to the familiar situation often witnessed wherein any minor and innocent motion imparted to the vehicle set off a loud and bothersome siren, often in the most inappropriate places.
Moreover, if the thief was sufficiently proficient, notwithstanding the setting off of visual or audible warning devices, the vehicle could nevertheless be started in a sufficiently short time and driven to a location where the warning device may be deactivated so as to effect the theft.
Still further, if the owner was not in proximity of the vehicle to disarm the alarm once it was set off, the disconcerting experience of coming back to a vehicle with a drained battery frequently resulted, often leaving the operator stranded. Moreover, with respect to some of these devices, the effective operation thereof might also drain the battery or render an override impossible so as to preclude starting the vehicle when desired.
Further difficulties with prior attempts to solve the serious and increasing problem of automobile theft are also related to these prior devices. Once a thief discovered how to override the theft prevention system, the vehicle would operate in a normal fashion. It would, however, be highly desirable to provide a system wherein even if the thief is otherwise able to override a protection system to put the vehicle into a position wherein the motor may be cranked, the vehicle will nevertheless simulate an inoperative condition as, for example, simulating the sound of a weakened or dead battery.
Another defect common to most prior art systems relating to their active nature was that they did not seek to simply monitor the normal and correct sequence of events encountered in an authorized starting of the vehicle to determine whether the start circuit should be energized to permit starting. In other words, none of the prior systems sought to simply monitor whether a proper normal sequence had occurred of insertion of a key into the ignition switch, followed within a relatively short and preselected period of time by the positioning of the switch in the start position to thereby energize the starting circuit to start the vehicle.
Other drawbacks of prior systems relate to their expense in terms of the cost of the system and its installation, as well as the complexity of the system and a frequent requirement for supplemental installation of additional wiring, components and the like.
Thus, it may be appreciated that a vehicle theft prevention system and method is highly desired which is of a simple, inexpensive and reliable design which might be readily installed on a number of different vehicles with minimum component installation and wiring. Such a system is further highly desired which is entirely passive, and thus can be employed in repeated sequences of starting and stopping of the vehicle without attendant acts of arming and disarming being required of the operator. Further, the system will in every respect appear to operate in the normal operational sequential steps of starting and stopping the vehicle.
A system is further desired in relation to this latter feature which simply monitors a normal sequence of starting events, the absence of which would signal unauthorized operation of the vehicle. It is also desirable to provide a system and method which, upon attempted theft, would simulate inoperability of the vehicle as, for example, in simulating the sound of a weak or dead battery. A system is further desired which, for the aforementioned redundancy and safety reasons, would require presence of two normally occurring events in order to permit starting of the vehicle, such as insertion of the proper key simultaneously occurring with the closing of the driver's door.